Newbie- considering buying 2 unit home with code violations

[Leah C.]

Hi all, two questions: is an old 2 unit house required to have 2 doors (or 2 egress options) and how much might I owe to fix it?

This is the first rental I'm seriously considering- it's on the west side, 2 units with an attic space. It was built in 1901 and the strange thing is it only has one door to enter the house and it's in the back with indoor stairs to each unit and no fire escapes- is this a huge violation I'd be responsible for if I buy?
Current owner is an older gentleman who's had it for 10 years and seems eager to sell, uninterested or unable to drop the money to fix it up.

I've searched everything, including the city building and fire codes but haven't found a straight forward answer (I really am a newbie). I'm wonder how the house has been sold over and over without that being flagged if it really is an issue. I thought there were certain exceptions for really old houses.
Is this something I could ask an alderman about? It seems simple enough to get a yes or no answer about.

If the two exits are required, I'm wondering if a fire escape can be built in the front windows since there's nothing there.

Before I make a decision and go chasing quotes from 50 companies, I'm wondering if anyone here has an estimated cost they'd be willing to share based on similar experiences?

Thank you so much in advance if you read this far!